近年來應用手術導引系統在髖關節表面置換手術(Hip Resurfacing Arthroplasty)已是成熟的技術，此一手術需將植入物的中心柱沿股骨頸的軸線方向植入，但是在解剖上對於此一軸線卻無嚴格的定義，故本研究的目的即在探討植入物的中心柱依各種軸線植入後對於股骨頸應力分佈之影響，以作為植入物中心柱植入準則的參考依據。
本研究針對所蒐集到的五種股骨頸軸線的定義，再將髖關節表面置換用的植入物依各種股骨頸軸線定義植入後，利用有限元素法進行應力分析，以比較各軸線模型的應力分布。並以完整股骨(Intact Femur)的應力分布作為比較的標準。分析的結果顯示最大安全通道為最佳的植入方向，但是各軸線模型的整體von Mises應力分布彼此的差異不到5%。為進一步找尋較佳的植入方向，便由最大安全通道方向設定偏斜10°的八個軸線模型，並進一步分析各軸線之間的應力分布差異。研究結果發現當植入物的軸線偏向最大安全通道上方、前方及後方都會令股骨頸的應力遮蔽效應變大而偏向下方時應力分布和完整股骨最為接近。因此進一步改變偏向下方的角度值進行應力分析，發現當下偏的角度在8°~17°時整體von Mises應力和完整股骨僅相差10%。故建議髖關節表面置用植入物的植入方向應選在最大安全通道下方8°~17°範圍內。

Recently hip resurfacing arthroplasty is a well developed technology. A key procedure of HRA is to implant the shaft of the femoral component along so called the axis of femoral neck. Unfortunately, in anatomy, there is no commonly established definition of the axis of femoral neck. Therefore, this study aims for investigating into the effect of the orientation of femoral component on stress distribution in the femoral neck and we expect that the result could be referred for the implantation of femoral component.
Five definitions of the axis of femoral neck from different literatures were collected. The shaft of the femoral component was implanted along each of these axes. The distribution of von Mises stress of femoral neck was analyzed by using finite element method. From the results of analysis, we found that the stress distribution of the model of max tunnel is closest to that of the intact femur model. In order to find better orientation of femoral axis, eight biased axis models regularly spread up 10° around the axis of max tunnel were analyzed, too. The results have shown that the models of biased axes superior, posterior, or anterior to max tunnel would make significant stress shielding to the femur. The model of biased axis inferior to the max tunnel had closest stress distribution to that of intact femur model. Again, to find better orientation of femoral axis, the biased axes with different spreading angle inferior to the max tunnel were investigated and analyzed. The results have shown that the difference of stress distribution between the intact femur model and the axes models with spreading angle between 8°~17° was within 10%. It is the best spreading angle to inferior for place implant. It is recommended to implant the femoral component along the axis 8°~17° inferior to the max tunnel.

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